Circular hydrogen: an ultra-fast thermal shock route to sustainable steelmaking

The steelmaking industry accounts for approximately 7% of global CO₂ emissions, highlighting the need for sustainable alternatives to conventional ironmaking. Green hydrogen offers a promising pathway but is limited by the high cost and complexity of current production technologies. This study presents a novel, ultra-fast, additive-free Thermal Shock Technique (TST) for converting waste plastics (e.g., rubber and face masks) and biomass (e.g., spent coffee grounds) into circular hydrogen. The process requires no feedstock pretreatment, catalysts, conductive additives, susceptors, or specialised equipment and can be performed using a conventional tubular furnace. TST achieves a hydrogen yield of 52.7 mmol g⁻¹ from plastic waste in <25 s, demonstrating exceptional reaction kinetics and operational simplicity. By converting waste into hydrogen-rich gas, TST demonstrates potential as a pathway for circular hydrogen production and possible future applications in steelmaking and other industrial sectors.